Abstract

Water, sanitation, and hygiene (WASH) interventions are amongst the most
crucial in humanitarian crises, although the impact of the different
WASH interventions on health outcomes remains unclear.

### Aim

To examine the quantity and quality of evidence on WASH interventions on
health outcomes in humanitarian crises, as well as evaluate current
evidence on their effectiveness against health outcomes in these
contexts.

### Methods

A systematic literature review was conducted of primary and grey
quantitative literature on WASH interventions measured against health
outcomes in humanitarian crises occurring Between 1980 and 2014.
Populations of interest were those resident in humanitarian settings,
with a focus on acute crisis and early recovery stages of humanitarian
crises in low and middle-income countries. Interventions of interest
were WASH-related, while outcomes of interest were health-related. Study
quality was assessed via STROBE/CONSORT criteria. Results were analyzed
descriptively, and PRISMA reporting was followed.

### Results

Of 3963 studies initially retrieved, only 6 published studies measured a
statistically significant change in health outcome as a result of a WASH
intervention. All 6 studies employed point-of-use (POU) water quality
interventions, with 50% using safe water storage (SWS) and 35% using
household water treatment (HWT). All 6 studies used self-reported
diarrhea outcomes, 2 studies also reported laboratory confirmed
outcomes, and 2 studies reported health treatment outcomes (e.g.
clinical admissions). 1 study measured WASH intervention success in
relation to both health and water quality outcomes; 1 study recorded
uptake (use of soap) as well as health outcomes. 2 studies were
unblinded randomized-controlled trials, while 4 were uncontrolled
longitudinal studies. 2 studies were graded as providing high quality
evidence; 3 studies provided moderate and 1 study low quality evidence.

### Conclusion

The current evidence base on the impact of WASH interventions on health
outcomes in humanitarian crises is extremely limited, and numerous
methodological limitations limit the ability to determine associative,
let alone causal, relationships.